<template>
  <div class="upload-file">
    <el-upload
      ref="upload"
      action="uploadFileUrl"
      :before-upload="handleBeforeUpload"
      :file-list="fileList"
      :limit="limit"
      multiple
      :on-exceed="handleExceed"
      :on-change="handleFileChange"
      :before-remove="handleFileRemove"
      :show-file-list="false"
      :auto-upload="false"
      class="upload-file-uploader"
    >
      <!-- 上传按钮 -->
      <el-button size="mini" type="primary">选取文件</el-button>
      <!-- 上传提示 -->
      <div v-if="showTip" slot="tip" class="el-upload__tip">
        请上传
        <template v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </template>
        <template v-if="fileType"> 且格式为 <b style="color: #f56c6c">{{ fileType.join(" / ") }}</b> </template>
        的文件
      </div>
    </el-upload>

    <!-- 文件列表 -->
    <transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
      <li v-for="(file, index) in fileList" :key="file.uid" class="el-upload-list__item ele-upload-list__item-content">
        <el-link :href="`${baseUrl}${file.url}`" :underline="false" target="_blank">
          <span class="el-icon-document"> {{ file.name }} </span>
        </el-link>
        <div class="ele-upload-list__item-content-action">
          <el-link :underline="false" type="danger" @click="handleDelete(index)">删除</el-link>
        </div>
      </li>
    </transition-group>
  </div>
</template>

<script>
import { uploadFile } from '@/api/documentation/management'

export default {
  name: 'FileUpload',
  props: {
    // 值
    value: {
      type: [String, Object, Array],
      default: null
    },
    // 数量限制
    limit: {
      type: Number,
      default: 5
    },
    // 大小限制(MB)
    fileSize: {
      type: Number,
      default: 5
    },
    // 文件类型, 例如['png', 'jpg', 'jpeg']
    fileType: {
      type: Array,
      default: () => [
        'gif', 'jpg', 'jpeg', 'png', 'bmp', 'webp',
        'mp4', 'm3u8', 'rmvb', 'avi', 'swf', '3gp', 'mkv', 'flv', 'mov',
        'mp3', 'wav', 'wma', 'ogg', 'aac', 'flac',
        'rar', 'zip', 'gz', 'bz2',
        'doc', 'docx', 'xls', 'xlsx', 'pdf', 'ppt', 'pptx', 'html', 'htm', 'txt', 'pages', 'epub', 'numbers', 'csv', 'keynote'
      ]
    },
    // 是否显示提示
    isShowTip: {
      type: Boolean,
      default: true
    },
    // 是否显示文件列表
    showFileList: {
      type: Boolean,
      default: false
    },
    // 上传地址
    uploadUrl: {
      type: String,
      default: '/common/upload'
    }
  },
  data() {
    return {
      fileList: [],
      fileName: []
    }
  },

  computed: {
    // 是否显示提示
    showTip() {
      return this.isShowTip && (this.fileType || this.fileSize)
    }
  },

  watch: {
    value: {
      handler(val) {
        if (val) {
          let temp = 1
          // 首先将值转为数组
          const list = Array.isArray(val) ? val : this.value.split(',')
          // 然后将数组转为对象数组
          this.fileList = list.map(item => {
            if (typeof item === 'string') {
              item = { name: item, url: item }
            }
            item.uid = item.uid || new Date().getTime() + temp++
            return item
          })
        } else {
          this.fileList = []
          return []
        }
      },
      deep: true,
      immediate: true
    }
  },
  methods: {
    // 上传前校检格式和大小
    handleBeforeUpload(file) {
      // 校检文件类型
      if (this.fileType) {
        let fileExtension = ''
        if (file.name.lastIndexOf('.') > -1) {
          fileExtension = file.name.slice(file.name.lastIndexOf('.') + 1)
        }
        const isTypeOk = this.fileType.some((type) => {
          if (file.type.indexOf(type) > -1) return true
          if (fileExtension && fileExtension.indexOf(type) > -1) return true
          return false
        })
        if (!isTypeOk) {
          this.$message.error(`文件格式不正确, 请上传${this.fileType.join('/')}格式文件!`)
          return false
        }
      }
      // 校检文件大小
      if (this.fileSize) {
        const isLt = file.size / 1024 / 1024 < this.fileSize
        if (!isLt) {
          this.$message.error(`上传文件大小不能超过 ${this.fileSize} MB!`)
          return false
        }
      }
      return true
    },

    // 文件个数超出
    handleExceed() {
      this.$message.error(`上传文件数量不能超过 ${this.limit} 个!`)
    },

    // 上传发生变化钩子
    handleFileChange(file, fileList) {
      this.fileList = fileList
    },
    // 删除之前钩子
    handleFileRemove(file, fileList) {
      this.fileList = fileList
    },
    // 提交上传文件
    submitFileForm() {
      const formData = new FormData()
      this.fileList.forEach(file => {
        formData.append('files', file.raw)
        this.fileName.push(file.name)
      })
      formData.append('fileName', this.fileName)
      uploadFile(formData).then(res => {
        console.log('上传结果', res)
      })
    },

    // 上传失败
    handleUploadError() {
      this.$message.error('上传失败, 请重试')
    },
    // 上传成功回调
    handleUploadSuccess(res, file) {
      if (res.code === 200) {
        this.$message.success('上传成功')
        this.fileList.push({ name: file.name, url: res.fileName, fileSize: file.size, uid: new Date().getTime() })
        this.$emit('input', this.fileList)
      }
    },
    // 删除文件
    handleDelete(index) {
      this.fileList.splice(index, 1)
      this.$emit('input', this.fileList)
    },
    // 获取文件名称
    getFileName(name) {
      if (name.lastIndexOf('/') > -1) {
        return name.slice(name.lastIndexOf('/') + 1).toLowerCase()
      } else {
        return ''
      }
    },
    // 对象转成指定字符串分隔
    listToString(list, separator) {
      let strs = ''
      separator = separator || ','
      for (const i in list) {
        strs += list[i].url + separator
      }
      return strs !== '' ? strs.substr(0, strs.length - 1) : ''
    }
  }
}
</script>

<style scoped lang="scss">
.upload-file-uploader {
  margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
  border: 1px solid #e4e7ed;
  line-height: 2;
  margin-bottom: 10px;
  position: relative;
}
.upload-file-list .ele-upload-list__item-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: inherit;
}
.ele-upload-list__item-content-action .el-link {
  margin-right: 10px;
}
</style>
